Composition of matter for and process of making insulating material.



1 UNITED sTAr s (ARL PATENT OFFICE.

A. KELLER AND BERT-RAM) G. JAMIESON. OF (.HllAGO, ILLINOIS.

Specification of Letters Patent.

Patented March 23, 1909.

Application filed December 26, 1907. Serial No. 408,186.

T 0 all whom it may concern:

Be it known that we, CARI, A. KELLER and BERTRAND G. JAMIESUN, citizens of the United States, residing at Chicago, in the county oi (.m k and State of Illinois, have invented certain new and i filffll Improvements in (lcn'ipositi\..iis cf Matter for and I I'UCPSSISklf'brlflklng Insilating Material, of which the following is a full, clear, concise, and exact description.

The object on electrical insiilaiin matcrialwhich is electrically indestructible and of high in lating properties, mechanically strong and capable cl inexpensive production. The mmpositicn f matter of our invention, when formed into insulatcrs in accordance with 01*! improved process, is also capable of resisting very high temperatures u'ithor-t dcterioration.

One cf the peculiarly advantageous was of the insulating material of our invention is for thc support liars upon a switchhcard, especially when the ins-lators are required to support considerable weight and to withstand high temperatures, the invention being usef .l in con necti'in with conch ctors which are covered with other insi lating material, as well as with bare conductors.

In general, the insulating material of our inventi-r'n consists of a composition of ccment and sand impregnated with an instlating' material in fluid form. In accordance with our invention, the mixture of sand, cement and \rateris preferably molded when in a plastic state into the required f. rni for suliscrpicnt i inixtre has become set, impregnated with fluid,

the moldcdforni is fluid state for the purpose of impregnating the molded forms. The particular fluid cm plo pled may lie of various kinds, such as oils, asp products, or various compounds or mixtures of these or other similar substanccs.

In the practice of our invention, we prefer to use a high gradc Portland cement, mixing it with fine sand in the proportions of approximately onc parts of sand. in place of the sand, it is possible to use granulated stone or crushed gravel of a size adapted to form a suitable concrete. We prefer to include in the sand of our invention is to provide f conductors, s ch as l'iIiS I After the cement an electrical insulating or with an electrical insulator which can be reduced by heating or otherwise to a altums, liitnniens, waxes or TGSiTnnis;

part of cement to ihrcrl a small 'iercciitage of binding sand which is line enough to pass through a fine mesh screen. We have found ten per cent. of this binding sand to give satisfactory result in certain instances, but the proper amount will vary with the coarseness of the balance (I the sand, as will be understood by those skilied in the art. The sand and cementsre mixed with sufficient water to wet the material and to cause it to set after it has been molded in molds having the form of the finished insulators. We prefer also to combine in this mixture a small quantity of any cf the well known Water proofing compounds. l For example, we may use one per cent. of a Water proofing compound containing a. stearic acid base, such as the Medusa compound. This admixture of a water proofing l compound aids in rendering the finished insrlatc-rs impervious to moisture. 1 Many of the mineral and ve etable oils which are usually employed for e ectrical n- I sulatiiig purposes may e used in carrying 1 out our invention. We prefer, however, to l use asphaltum base. The preferred method of impregnating the cement insulator forms is to heat them to a high degree of tempera ture, thus expelling all of the moisture from i the pores of the form. While still hot, the iforni is then plunged into the insulating i fluid, which is absorbed until the pores of the insulator are saturated. This impreglnation of the pores may be accomplished E wholly or in part by boiling the fluid in which i the insulator forms have been immersed. Thc boiling is continued ireferabl ,for a l number cl hours, and nnti the moisture is i from the pores of the insulator the 'porcs licing tilled in turn with the lpon the removal oi the insulators from the bath of insulating fluid, the insulating material is permitted to dry or harden as the casc may lit,JA'lHltlllHlll the insulators arc ilii(l for use. k The proportion of the fluid ingredients with ii-spccl lo the other component parts l of the mixture depends no alccrtain extent upon the physical forms into which the composition is nioldcd, also upon the size of the pores in the moldcd forms. By proceeding as we have dcscril'icd, there is. however, no dillirulty in securing the proportions suitable for the purpose. \lh'ilc tho impregnation ol' the molded forms after they have taken their linal set is i the preferred method, it will be apparent to expelled livid.

(ill

llll) llllv l l o those skilled in the art that the insulating fluid ma? be combinedwith the other elements 0 the composition in various other ways, and we do not wish therefore to be limited to the recise method of procedure which we have erein described in detail.

Our invention provides insulators which are not liable to water absorption, the pres ence of which is likely to destroy the menlating value of a porous medium. The insulating fluids which are used in carrying out our invention manifestly cannot be used for purposes in which strength and rigidity are 5 re uircd, except by the use of our invention.

aving described our invention therefore,

we claim as new and desire to secure by Letters Patent:

1. 'lhe recess of forming an electrical insulator w ich consists in mixing hydraulic cement, sand, waterproofing compound and water, molding said mixture, solidifying the molded form, evaporating the water therefrom, heatin the orm, and impregnating it while beats with an asphaltum insulating fluid.

2. The herein described composition of matter which consists of sand an hydraulic cement in the approximate proportions of three to one, a saponifiable water roofing compound, and an insulating mcdiun reducible to fluid form.

'3. The herein described composition of matto r which consists of sand, cement and a saponlfiable water )roofing compound impregnated with a uid insulating material.

4. 'lhe process of for'rning a n electrical Insulator which consists in min ng cement, l

sand, water-proofing compound and water,

y molding said mixture, solidifying the molded form, evaporating the water therefrom, heat- 1 ing the orm, and impre nating it while heated with an insulating uid. 5. The rocess of forming an electrical insolator which consists in mixing cement. sand, waterproofing com ound and water, molding said mixture, solic ifying the molded I form, heating the form to expel all moisture l and a large part of the air therefrom, and impregnating it while heated with an insulatmg fluid.

6. The recess of forming an electrical in- 1 sulator w ich consists in mixing hydraulic cement, sand, water-proofing compound and water, molding said mixture, solidifyiii' the molded form, evaporating the water thcrc l from, heating the form, and then heating it I in a fluid insulating material of solid (onsistencv under normal tem )eraturcs.

\ 1. 'lhc herein (lGSClibBt composition of l matter which consists of sand and hydraulic lccment in the approximate proportions of three to one, stearic acid compound, and an instlating medium reducible to fluid form.

8. 'l he herein described composition of l matter which consists of sand, cement and l stearic acid compound impregnated with a l fluid ins: lating material.

In witness whereof we hereunto subscribe our names this 24th'day of December, A. l). 5 1907.

l CARL A. KELLER. j BERTRAND G. JAMIESON.

Witnesses LYNN A. WILLIAMs,

l-havnr L. Hanson. 

